Heat regenerator particularly hot blast stoves for a blast furnace

ABSTRACT

A hot blast stove or heat generator for blast furnaces with structure for improving the mixture and combustion of the gas and air fuel components within the combustion chamber, wherein the improved structure includes coaxially disposed but nonintercommunicating center and annularly encircling conduits for supplying respectively the gaseous fuel and air components with a pressure and flow equalizing rod lattice in one or both of the respective conduits. A preferred form utilizes two axially spaced lattices in the gas conduit and one in the air conduit, each of which is adjustable from outside of the furnace to help vary and better equalize the respective flows over the respective cross sections of the conduits.

United States Patent Jacobus Van Laar BLAST STOVES FOR A BLAST FURNACE 6Clalms, 2 Drawing Figs.

Int. Cl

Field of Search [56] References Cited UNITED STATES PATENTS 1,849,6573/1932 Boynton 263/19 2,514,768 7/1950 Kennedy 431/187 X 2,582,5771/1952 Fink et a1 431/346)( Primary Examiner- Edward G. FavorsAtmrneyWenderoth, Lind and Pona-ck ABSTRACT: A hot blast stove or heatgenerator for blast furnaces with structure for improving the mixtureand combustion of the gas and air fuel components within the combustionchamber, wherein the improved structure includes coaxially disposed butnonintercommunicating center and annularly encircling conduits forsupplying respectively the gaseous fuel and air components with apressure and flow equalizing rod lattice in one or both of therespective conduits. A preferred form utilizes two axially spacedlattices in the gas conduit and one in the air conduit, each of which isadjustable from outside of the furnace to help vary and better equalizethe respective flows over the respective cross sections of the conduits.

ll lllEAT REGlENlElltA'llGllt, PARTICULARLY llllOT BLAST STOVES ll Olk ABLAST ll lUlltNA ClE I The invention relates to a heat regeneratorparticularly a hot blast stove for blast furnaces with a vertical burnerinstalled inside the combustion chamber having one vertical conduit forthe supply of gaseous fuel and a second conduit coaxial with the firstconduit for the supply of combustion air.

Hot blast stoves for blast furnaces are generally used to increase theefficiency degree of a blast furnace by heating the so-called windbefore it blows into the blast furnace. For this purpose the wind is ledthrough the hot blast stove, once the stove has been preheated by thecombustion of gas. Hot blast stoves are known having a combustionchamber located inside and outside, which means that the chamber wherethe combustion takes place can be inside or outside a structure whichcontains a lattice work which is to be heated by the combustion air.This invention refers to both types of hot blast stoves as well as toother similar heat generators which for instance are common in theceramic industry. Lately vertical, and mainly ceramic burners have beendeveloped for hot blast stoves, which allow a more complete combustionof the gaseous fuel and at the same time preserve better the walls ofthe combustion chamber than the common burners. By giving the burner anadequate shape it has been achieved that the mixture of gas and air wereimproved to such an extent that the combustion became more economical.

Nevertheless it was proven that even by using the most modern burners,up in the combustion chamber there still was to be found unburned gas.Supposedly this occurs because of an incomplete mixture of gas and air.It has also been discovered that this happens essentially due to anuneven distribution of gas and air over the cross sections of the airand gas conduits, which can have a great influence upon the large crosssections to be considered here.

An object of the invention is to improve the distribution of gas andair, by putting into at least the first and/or second conduit anadjustable device which equalizes the pressure over the cross section ofthe conduit.

It has been previously proposed to narrow the conduits shortly beforethe exit opening, in order to improve the flow condition. It has beenproven that this measure alone does not suffice, particularly when thehot blast stove is operated under different circumstances.

It is more advantageous when the pressure-equalizing devices can beadjusted from outside the hot blast stove. In this manner the air andgas distribution can be adapted to almost any working condition.

Pressure-equalizing devices can be gratings, strainers, louvered flapsystems, etc. The best results for the operation of a hot blast stovehave been obtained with pressure-equalizing devices in the shape of rodlattices.

It is conceivable to further improve the distribution of gas and air inboth conduits by installing several lattices. According to the inventionan optimal operation can be achieved with two lattices in the gasconduit and one lattice in the air conduit. A further improvement can beobtained by narrowing the conduits, and by placing a lattice in thenarrowed part of each conduit.

Actually such narrowing of the conduits is known. A certain improvementof the combustion could be attained formerly thanks to such narrowings.But only by placing lattices in the narrowed conduit parts can the bestresults be obtained.

The improved results due to the invention can be obtained when using iton hot blast stoves with interior and exterior combustion chambers.

Further objects of the invention and details of the advantages gainedare illustrative hereafter in the drawings which schematically show anexample of operation of an installation according to the invention,wherein:

FIG. 1 shows a longitudinal section of a hot blast stove with aninterior combustion chamber.

FIG. 2 shows the burner of the hot blast stove of FIG. l on a largerscale.

In FIG. l the housing ll of a hot blast stove forms with the bottom 2 onwhich it stands a bricked unit. The brick housing l is surrounded by asteel casing (not shown). A number of pillars 3 projecting out of thebottom 2 support a lattice 4, which in its turn supports the perforatedstones piled up on it (not shown) through which alternately hotcombustion gas goes down and heated air is led upwards. This so-calledlattice work is separated by a wall 5 from the combustion chamber, whichin turn is limited outside by a section of the housing l.

The hot blast stove is closed on the upper part by a brick cupola t5 anda steel cupola 7.

The gaseous fuel and air needed to preserve the hot combustion gases aresupplied through a conduit and/or through a ring conduit 9 to burner 10.The burner is schematically shown in FIG. ll.

Above the burner lllll the fuel and air are intimately mixed and thefuel is burnt in the combustion chamber. The hot combustion gases areled over separation wall 5 downwardly. Once the piled up stones in thelattice work are sufficiently heated the supply openings M and R5 of thefuel and air conduits 8 and/or 9 are closed.

The air to be heated is then led through an opening ill in oppositedirection through the installation and can escape through opening 12.

FIG. 2 shows a burner and its surroundings in detail and on a largerscale.

The central conduit for the fuel connects with a central hole 116 in theburner 10. This burner is manufactured of ceramic material, as well asthe walls of the conduits d and 9 and the walls l and 5 of thecombustion chamber.

In the upper surface 18 of the burner 10, discharge slotshaped openings117, are in connection with conduit 9.

With an adequate shape of the burner an almost optimal mixture of thefuel and the air can be obtained under the condition that the fuel andthe air are actually equally distributed over the cross section of thehole in, and/or the openings 117. The latter is obtained when narrowingconduits d and 9, and by installing rod lattices. The narrowing in theconduits and 9 are shown at 119 and/or 20 in FIG. 2.

In conduit 8 two rod lattices have been provided, lattice 21 in thenarrowed conduit part 119, and a second lattice 22 not far from thelower end of conduit 8. In ring conduit 9 there is only a singlering-shaped rod lattice 23 in the narrowed conduit part 20. Any suitablemeans for effecting adjustment of the pressureand flow-equalizing meansmay be utilized such as schematically depicted louvre traps 2d (FIG. 1)adjustable by any suitable control, such as handle 25.

When operating such a hot blast stove almost no unburned fuel remainderscan be measured in the cupola and under the lattice work, whichindicates an almost complete combustion.

We claim:

ll. In a heat generator, particularly a hot blast stove for blastfurnaces having a vertical burner installed inside of a combustionchamber, improved means for providing a more even mixture and completecombustion of gaseous fuel components, said improved means comprising afirst vertical conduit for and connectable with a supply of gaseousfuel, a second conduit coaxial with said first conduit for andconnectable with a supply of combustion air, pressureand flowequalizingmeans in at least one of said conduits to equalize the pressure and flowmore completely over the cross section of said conduit to form an evenand more regular mixture of gaseous fuel, and said first and secondconduits being separately, noncommunicatively disposed with theirrespective outlets relatively concentrically spaced from one another sothat responsive to the even and more regular flowing of the gaseous fuelcomponents, the intermixing of the fuel components and the subsequentcombustion occurs above said burner in the combustion chamber resultingin a more efficient and complete combustion.

2. A heat generator according to claim 1 wherein saidpressure-equalizing means include means to enable them to be adjustablefrom the outside of the hot blast furnace, for instance, the inclusionof movable louvered traps.

duits are respectively narrowed down and a lattice is disposed in thenarrowed part of each conduit.

6. A heat generator according to claim 1 wherein operable louver trapsare disposed as the pressure-equalizing means and having adjustabledevices operably connected therewith for adjusting same from outside thegenerator.

1. In a heat generator, particularly a hot blast stove for blast furnaces having a vertical burner installed inside of a combustion chamber, improved means for providing a more even mixture and complete combustion of gaseous fuel components, said improved means comprising a first vertical conduit for and connectable with a supply of gaseous fuel, a second conduit coaxial with said first conduit for and connectable with a supply of combustion air, pressure- and flow-equalizing means in at least one of said conduits to equalize the pressure and flow more completely over the cross section of said conduit to form an even and more regular mixture of gaseous fuel, and said first and second conduits being separately, noncommunicatively disposed with their respective outlets relatively concentrically spaced from one another so that responsive to the even and more regular flowing of the gaseous fuel components, the intermixing of the fuel components and the subsequent combustion occurs above said burner in the combustion chamber resulting in a more efficient and complete combustion.
 2. A heat generator according to claim 1 wherein said pressure-equalizing means include means to enable them to be adjustable from the outside of the hot blast furnace, for instance, the inclusion of movable louvered traps.
 3. A heat generator according to claim 1 wherein said pressure-equalizing means are in the form of rod lattices.
 4. A heat generator according to claim 1 wherein said pressure-equalizing means comprises consecutively two relatively spaced lattices in the gas conduit, and further includes a lattice assembly in the air conduit.
 5. A heat generator according to claim 1 wherein said conduits are respectively narrowed down and a lattice is disposed in the narrowed part of each conduit.
 6. A heat generator according to claim 1 wherein operable louver traps are disposed as the pressure-equalizing means and having adjustable devices operably connected therewith for adjusting same from outside the generator. 